OSAKA – Roofing tiles used in up to 5 million homes in Japan — 20 percent of the total — are believed to contain asbestos, tile makers said Saturday.
The tiles include those made by Kubota Corp. between 1961 and 2001 and by the Matsushita Electric Works group between 1971 and 2003.
Asbestos, a naturally occurring mineral fiber, is known to cause health problems, including lung cancer and mesothelioma, a rare form of cancer. Experts say the roofing tiles can scatter asbestos when damaged or demolished.
The report could force the government and housing industries to take further preventive measures.
The cement tiles are 25 percent asbestos, the makers said, adding asbestos-free tiles are the only type they now manufacture.
The cement-asbestos products were popular because they weigh less than the traditional Japanese-style roof tiles made of clay and cause less damage to houses during earthquakes.
Kubota Matsushitadenko Exterior Works Ltd., a company created in 2003 through a business tieup between Kubota and Matsushita Electric Works, said about 600 million sq. meters of roofing tiles with asbestos have been sold by the two companies. The amount was enough to cover about 6 million houses.
Roughly 4 million to 5 million of the houses are estimated to still be in use, while the rest are likely to have been demolished.
Daiken Corp. and the roofing material maker Yamato Slate both said they had manufactured or sold such tiles.
A Kubota Matsushitadenko official said there is little possibility the tiles scatter asbestos “if used in a normal manner.”
But experts point out that compared with demolition work for schools and other public facilities, measures to prevent asbestos from getting into the air when homes are torn down are insufficient.
Industry sources say roof tiles are often destroyed by “smashing them on the ground” when houses are being demolished.
The Ministry of Economy, Trade and Industry says it is still investigating how much asbestos-containing housing construction materials have been produced in the past.
Besides roof tiles, asbestos has been widely used in other construction materials, such as outer walls. An industry insider estimates that asbestos-containing products have been used in some form in about 70 percent of Japan’s houses.
Dozens of companies have been disclosing information since late June on asbestos-related deaths of hundreds of workers at their factories.
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